In terms of gameplay, needing to discard an Energy each time for the already costly Fire Blast may seem cumbersome, but its 90 damage could quickly turn the tide depending on early game situations
This is not as flexible as Introduction to Annihilation or Scour from Existence, but its cheaper and got more uses
Attrition (Sacrifice Black Enchantment) A flexible and fearsome sac outlet, [c]Attrition[/c] allows you to turn your creatures into [c]Doom Blades[/c]
Commander Nicol Bolas, the Ravager is the most unique in the game, transforming into Planeswalker Nicol Bolas, Arisen
Scrooge McDuck - Resourceful Miser The first entry on this list not coming from an older expansion, Scrooge McDuck - Resourceful Miser is one of Sapphires dastardly mid-game drops
If you would like some repeated trips into the Dungeon you can try Yuan-Ti Fang Blade